#include <cstdio>
int n,a[10000001],s;
void H(){//筛法函数，上面解释过了
    for (int i=1;i<=n;i++){
        for (int j=i;j<=n;j+=i)a[j]++;
        s+=a[i];
    }
}
int main(){
    scanf ("%d",&n);
    H();
    printf ("%d",s);//输出
    return 0;
}
